This invention relates generally to a through-the-wall sleeve for a packaged terminal air conditioning unit. More specifically, the present invention relates to a non-metallic wall sleeve including an improved mounting means for securing the chassis of a packaged terminal air conditioning unit having an L-shaped weather strip angle to the flange of the sleeve.
Air conditioning units which are commonly used for light commercial applications such as hotels, dormitories, and office buildings often are of the type known as a packaged terminal air conditioner. These packaged terminal air conditioners extend through the wall of the enclosure and normally have a condensing section located in communication with the ambient air for discharging heat energy. An evaporator section is provided in communication with the enclosure air for conditioning said air as it is drawn through the unit. Packaged terminal air conditioning units may be designed such that a portion of the unit is encased within the wall in a sleeve. The remaining portion of the unit is typically located within the enclosure to be conditioned and has readily accessible controls thereon and is encased within a decorative cover.
Normally, through-the-wall installation can be made in masonry or wood frame walls by installing the sleeve through the wall during the construction of the building and installing the air conditioning unit in the sleeve upon completion of the building.
Previous wall sleeves for packaged terminal air conditioners have been constructed from metal sheets (these sleeves will also accept heat pump units and the like). This type of wall sleeve comprises a box formed by a top, a bottom, and two sides, but having the front and back open. Generally, a grille is fastened to the rear or outside opening, while the air conditioner unit is introduced into the sleeve through the front opening. The front opening of the sleeve is bound by a flange or molding formed by bending the front edges of the top, the two sides and the bottom at right angles to form four flanges lying in the same plane with the long leg of an L-shaped weather sealing flange attached vertically along the sides of the air conditioning unit chassis. Accordingly, when the unit chassis is introduced into the sleeve the short leg of the L-shaped weather sealing flange mates perpendicularly with the side flanges on the sleeve while a gap is left between the flange of the sleeve and the long leg of the weather sealing flange of the air conditioning unit. Gasket material or weather tight caulking is generally applied in the gap between the sleeve and the air conditioning unit to insure a weather tight installation. However, when screws installed through the weather sealing flange of the air conditioning unit and the flange of the wall sleeve are tightened to secure the air conditioner chassis to the sleeve, the metal flange of the sleeve is distorted as the weather tight caulking is compressed between the wall sleeve and the air conditioning unit. This distortion of the flanges was not detrimental to the metal sleeve, since the material around the fastener holes in the sleeve was not broken and the air conditioning unit could be removed and replaced and the mounting screws could still be secured through the weather sealing flange to the distorted wall sleeve flange.
However, with the introduction of non-metallic sleeves, the flanges on the sleeves did not distort when the mounting screws for securing the air conditioning unit chassis to the flanges of the sleeve were tightened, but the sleeve flange fractured because the sleeve flange was pulled into contact with the long leg of the L-shaped weather sealing flange of the chassis. This problem was solved, however, by ensuring that a pad of material around the screw hole in the sleeve flange was loaded in compression when the chassis was inserted in and fastened to the sleeve. The material was loaded in compression by installing a standoff around the screw hole which made contact with the long leg of the L-shaped flange. However, under certain conditions the sleeve flange could not be loaded in compression, and could still be broken when the chassis was fastened to the sleeve. For example, when the chassis was prevented from sliding completely into the sleeve by a foreign object in the sleeve, the L-shaped weather sealing flange of the chassis did not contact the standoff and when the fastener was over torqued, the sleeve flange broke.